This invention relates to equipment that can be used in the drilling and completion of oil and gas wells, in production of hydrocarbons from such wells, and in other operations in such wells.
Hydrocarbon fluids such as oil and natural gas are obtained from a subterranean geologic formation (a xe2x80x9creservoirxe2x80x9d) by drilling a well that penetrates the hydrocarbon-bearing formation. Once a wellbore has been drilled, the well must be completed before hydrocarbons can be produced from the well. Completion generally includes the installation of casing and one or more tubing strings in the wellbore, cementing, the installation of a variety of downhole equipment, such as packers and flow control devices, and in most cases perforating the casing to allow the hydrocarbons to flow from the formation into the wellbore.
After a well is completed and production of hydrocarbon fluids begins, there are a number of situations in which it is necessary to lower mechanical and/or electrical apparatus into the well to perform various operations. Such apparatus is commonly attached to a wireline and lowered into the well to the desired depth. However, the space available in which to lower such devices is lirnited, taking into account the size of the well casing and the tubing located within the casing, and also taking into account the apparatus (such as packers, safety valves, mandrels, and the like) that are typically located at various depths in a well. Generally, the devices that are to be lowered into the well must have a profile, in a horizontal cross-section, that is smaller than the opening (e.g., the inner diameter of the production tubing in the well) through which it will pass. This physical size constraint is a major problem in the design and operation of well equipment.
There is a long-standing need for improved equipment and methods for lowering apparatus into oil and gas wells, such that the apparatus can perform one or more useful functions downhole in the well. There is also a need to reduce the space required and the weight loads imposed on the well location xe2x80x9cfootprint,xe2x80x9d the surface area on which work related to the well is performed.
The present invention relates to apparatus for use in a wellbore that comprises (1) a first structure that comprises (a) at least one extendable member that can be reconfigured from a coiled form to an extended form, the member having a flattened transverse cross-section when in the coiled form and a curved transverse cross-section when in the extended form, (b) a downhole well tool attached to the extendable member, and (c) a housing in which the extendable member can be coiled; (2) a well mounting device for supporting the first structure from the wellbore or the surface of a well; and (3) means for reconfiguring the extendable, coilable member in a wellbore from the coiled form to the extended form. The present invention also relates to methods of using such apparatus in a wellbore.
Preferably, the extendable member is reversibly configurable between the coiled form and the extended form. In other words, the member can be initially in the coiled form, and can be extended, and later retracted back into the coiled form. Preferably, this reconfiguration can be repeated many times.
In a preferred embodiment of the invention, the extendable member has a substantially planar cross-section when in the coiled form. xe2x80x9cSubstantially planarxe2x80x9d in this context means that the member is nearly flat if not entirely so when viewed in a cross-section transverse to the member""s longitudinal axis. In the extended form, preferably the member has circular, semi-circular, oval, or semi-oval transverse cross-section, although other cross-sectional configurations are possible as well.
The well mounting device can be, for example, a wireline, well tubing, well casing, or coiled tubing. The means for reconfiguring the extendable member can comprise, for example, a spool and electric motor for spooling and unspooling the member.
Specific examples of the present invention include laterally extendable bottom hole assemblies that comprise a sensor module (for measuring pressure, temperature, pH, flow rate, or other wellbore parameters), wrappable downhole sensor assemblies, dual function umbilical-wireline structures, coiled tubing inspection tools, and corrosion-resistant coiled tubing liners.
Various embodiments of the present invention have one or more advantages compared to prior equipment and methods. Equipment of the present invention comprising bistable members can be relatively light and compact, and can be controlled from a remote location. The compactness of such devices can offer significant design flexibility, because the bistable members can expand to a relatively large size in comparison to the space they take up in coiled form. Equipment according to the present invention will in many situations also be relatively easy to install in a wellbore. Further, in certain embodiments, when the bistable member is extended, it has sufficient strength to be self-supporting. The present invention can also provide flexibility in delivering well tools downhole, in that equipment comprising the bistable member can be connected to conventional well tubing, a wireline, or coiled tubing, among other approaches.